Routing information packets in a distributed network

ABSTRACT

Information packets are routed through a distributed routing network by determining a forwarding equivalency class (FEC) for each subscriber unit accessing the network. The FEC to which each subscriber unit belongs is based on the point at which the subscriber unit accesses the network. The forwarding equivalency class for each subscriber unit is updated if the subscriber unit accesses the network at a different point. Information packets are routed from a distribution point by determining the next point connected to the distribution point based on the forwarding equivalency class for the destination subscriber unit specified in the packet.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.09/603,123 filed Jun. 23, 2000 now U.S. Pat. No. 6,831,902, thespecification of which is expressly incorporated herein by reference inits entirety. This application claims the benefit of U.S. ProvisionalApplication No. 60/152,730 filed Sep. 8, 1999, titled “CellularizedPacketized Voice and Data,” the specification of which is expresslyincorporated herein by reference in its entirety. This applicationclaims the benefit of a U.S. Provisional Application No. 60/185,788filed Feb. 29, 2000, titled “High Speed Distributed WirelessCommunication,” the specification of which is expressly incorporatedherein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to routing information packets destinedfor possibly mobile or portable subscriber units through a distributedcommunication network.

BACKGROUND ART

Communication systems are increasingly being required to provide a widerange of services, including different forms of information communicatedand different communication characteristics. Information forms includevoice, data, video, telemetry, and the like. Communicationcharacteristics include quality, complexity, latency, reliability, cost,availability, portability, and the like. Infrastructure such astelecommunication systems, the Internet, and cable systems exist toprovide long-haul routing and information content sourcing. However,difficulty remains in delivering this information to customers. This isparticularly the case if the customer is located in a rural location, iscommunicating through portable equipment, or is mobile.

Traditionally, communication service providers have relied on copperwire or coaxial cable to connect distribution sites and subscriberpremises. However, increases in the number of users, number and type ofcommunication devices per user, and the information rate per device hasstrained the ability for traditional communication systems to providethe necessary bandwidth and flexibility. Various technologies includingdigital subscriber line (DSL) and video modems offer broadband access tothe subscriber over existing copper or coaxial loop technologies.Fiber-to-the-home offers broadband access through additional wirelineconnections. While each technology has broadband delivery properties,each is subject to physical and signaling limitations that restrictavailability in certain locations and for certain applications. Forexample, VDSL is limited to within approximately one kilometer of aconnecting central office. Further, each central office usually cannotsupport high-speed access for every customer within the central officecoverage area. Similarly, service provided by two-way cable modems islimited to the installation of coax, hybrid fiber coax and fiber-basedsystems by the cable provider as well as support capabilities of thesupporting central office. Currently, many premises do not have accessto high-speed wireline voice, data, and video services due, in part, tothe expense and difficulty in constructing or expanding central offices.

Wireless systems, such as PCS and cellular systems, offer an alternativeto wireline services. Typically, wireless systems include a centralizedmobile switching center (MSC) responsible for routing calls, trackinguser locations, billing information, and connectivity with othercommunication systems. The MSC is connected to base station controllers(BSCs), each of which supports one or more base transceiver stations(BTSs). Each BTS supports one or more cells based on the number andconfiguration of antennas supported by the BTS. Customers communicatewith the wireless system through radio telephones when the telephone iswithin the coverage range of a cell. When a call is placed, acircuit-switched connection is established from the telephone, throughthe BTS and BSC, to the MSC. The MSC determines the destination and, ifthe destination is to another telephone within the wireless system,establishes a circuit-switched connection to the destination telephone.If the destination is outside of the wireless system, the MSC routes thecall to a service provider for the outside destination.

Cellular and PCS wireless systems have traditionally focused on voice.However, recent introduction of digital radio in both the 800 MHZ and1.9 GHz permits low-speed data services, such as text messaging andone-way paging, to be implemented. Also, wireless modems implementingwireless application protocols may be incorporated into hand-helddevices such as lap top personal computers and personal digitalassistants (PDAs). Such devices may offer access to the Internet atrates up to 19.2 kilobits per second.

Several problems have developed with traditional wireless systems.First, because all calls are processed by the central MSC, it can becomea bottleneck limiting the number of users supported. Second, if the MSCfails, the system becomes inoperative. Third, the BSC and BTSarchitecture is fairly rigid, requiring manual reconfiguration in theMSC when components are added or deleted. Fourth, circuit-switchedchannel connections establish an upper bandwidth, limiting communicationrates. Fifth, bandwidth is wasted if the communication rate does notreach the maximum established by the communication channel. Sixth,high-speed data and video applications are impractical on wirelesstelecommunication systems designed primarily for voice.

An alternative wireless communication system is the multi-channelmultipoint distribution system (MMDS). In MMDS, an antenna broadcastshigh-bandwidth content to local receiving antennas. In the case ofInternet access, the return path is typically through slow telephonelines. MMDS, like wireline cable systems, is asymmetrical, making itbest suited for distribution of one-way entertainment signals such astelevision. MMDS also typically operates at a higher carrier frequencythan PCS systems, requiring receiving antennas to be positioned inline-of-site with the transmitting antenna. MMDS is typically deployedin a single cell broadcast architecture. Other wireless communicationsystems, such as local multipoint distribution system (LMDS) may bedeployed in a cellular fashion. However, because these systems typicallyoperate at a high carrier frequency, receiving antennas must bepositioned in line-of-sight with the transmitting antenna.

What is needed is a communication system that provides voice, data, andvideo signals at rates appropriate for each user. The system should makeefficient use of bandwidth, allocating only the bandwidth necessary fora particular communication. The system should be flexible, permittingautomatic addition and deletion of network components. The system shouldhave distributed routing and service provisioning to preventbottlenecks, permit scaling, and increase reliability and robustness.The system should support wireless subscriber units, accommodating awide variety of fixed, portable, and mobile user communication devices.The system should support high-speed symmetric communication forapplications such as video conferencing, real-time distributed documentsharing, and the like. The system should also easily and rapidly adaptto mobile and portable users that change location throughout thecommunication system.

DISCLOSURE OF INVENTION

The present invention provides automatic and flexible routing ofinformation packet through a distributed communication system. Thispermits users to enter the communication system at any point and tofreely move about within the communication system without having toregister or otherwise manually notify the communication system.

Information packets are routed through a distributed routing network bydetermining a forwarding equivalency class (FEC) for each subscriberunit accessing the network. The FEC to which each subscriber unitbelongs is based on the point at which the subscriber unit accesses thenetwork. The forwarding equivalency class for each subscriber unit isupdated if the subscriber unit accesses the network at a differentpoint. Information packets are routed from a distribution point bydetermining the next point connected to the distribution point based onthe (FEC) for the destination subscriber unit specified in the packet.Packets are preferably IP packets, but any form of packetizedinformation may be routed in this manner.

The communication system may include a plurality of access points. Eachaccess point transmits packets to and receives packets from at least onesubscriber unit accessing the communication system through the accesspoint. The communication system also includes a plurality ofdistribution points for routing packets. The access points anddistribution points form a distributed network with each distributionpoint directly communicating with at least one other distribution pointand each access point directly communicating with at least onedistribution point. Each distribution point routs information packetsbased on the forwarding equivalency class for a recipient subscriberunit specified in the information packet. Access points may be inwireless or wireline communication with distribution points or may bebuilt into distribution points. Distribution points may beinterconnected through wireline or wireless means. Subscriber units maybe in wireless or wireline contact with access points although,preferably, portable and mobile subscriber units are in wirelesscommunication with access points.

Updating of forwarding equivalency classes may be accomplished byseveral techniques. An access point determining that a new subscriberunit seeks access to the communication system through itself maybroadcast this information to the distribution points. Similarly, anaccess point determining that a subscriber unit is no longer accessingthe communication system through itself may broadcast this information.The communication system may also include a supervisor in contact withthe distribution points for determining membership in forwardingequivalency classes.

The above objects and features as well as other objects, features, andadvantages of the present invention are readily apparent from thefollowing detailed description of the best mode for carrying out theinvention when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic drawing illustrating a portion of a communicationsystem according to an embodiment of the present invention;

FIG. 2 is a block diagram of a distribution point according to anembodiment of the present invention;

FIG. 3 is a schematic drawing illustrating an implementation of acommunication system according to an embodiment of the presentinvention;

FIG. 4 is a schematic drawing illustrating an initial state for acommunication system according to an embodiment of the presentinvention;

FIG. 5 is a schematic drawing illustrating the addition of a secondaccess point to the communication system of FIG. 4 according to anembodiment of the present invention;

FIG. 6 is a schematic drawing illustrating a hierarchical routing systemusing ATM/IP switches according to an embodiment of the presentinvention;

FIG. 7 is a schematic drawing illustrating a network of distributionpoints routing packets based on forwarding equivalency classes; and

FIG. 8 is a schematic drawing illustrating forwarding equivalency classupdating to track a moving subscriber unit.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring to FIG. 1, a schematic drawing illustrating a portion of acommunication system according to an embodiment of the present inventionis shown. A communication system, shown generally by 20, includes aplurality of access points 22 which may be, for example, a local radioaccess point (LRAP). Each access point 22 defines coverage area 24 suchas, for example, a cell, covering a reception range of access point 22.Coverage area 24 may be formed from many independent sectors, as mayresult if access point 22 uses many unidirectional antennas, or may be asingle region resulting from the use of an omnidirectional antenna.Subscriber unit 26 within coverage area 24 may establish two-waywireless link 28 with access point 22. Subscriber unit 26 may alsoestablish wireline link 29 with access point 22. Links 28, 29 may besymmetrical or asymmetrical. Subscriber unit 26 may be fixed ornon-fixed and, if non-fixed, may posses varying degrees of portabilityand mobility. Subscriber unit 26 may be a mobile telephone, a computer,a video receiver, an audio receiver, a two-way video conferencingstation, a video game, an information kiosk, a remote sensor, a remoteactuator, or any other suitable communication device.

Wireless link 28 may be any form of electromagnetic signaling notconfined to a wire or cable, including energy radiated by antenna aswell as visible and invisible light. As will be appreciated by one ofordinary skill in the art, wireless link 28 may be implemented by anyaccess technology, including CDMA, TDMA, FDMA, OFDM, analog, and thelike. Modulation techniques that may be used with the present inventioninclude FSK, BPSK, QPSK, m-ary QAM, FM, AM, and the like. Further, theinvention does not depend on modulation frequency or on the use of FDDor TDD. In a preferred embodiment, the access technology, frequency, andmodulation method for establishing wireless link 28 are based, in part,on local geography, local regulations, noise and distortion sources,other operating wireless systems, cost, or any other suitable parameter.Subscriber unit 26 and access point 22 may establish wireless link 28using a plurality of combinations of access technology, frequency, andmodulation techniques.

Information transmitted on links 28, 29 may represent voice, data,video, streaming audio, streaming video, or the like. Types ofinformation include speech, facsimile, computer data, entertainment andinformational audio and video, video game data, telemetry information,security information, and the like. If the information occurs as acontinuous stream, subscriber unit 26 breaks the information intopackets prior to packet transmission and reassembles the informationstream from packets after packet reception. Any type of information thatexists in packets or that may be packetized can be used with the presentinvention.

In an embodiment of the present invention, subscriber unit 26 may beimplemented as part of terminal network controller 30 accepting inputsfrom and providing outputs to information sources including voiceequipment 32, computing equipment 34, telemetry equipment 36, videoequipment 38, or any other suitable communication equipment. Inputs toterminal network controller 30 may include serial data, parallel data,ISDN, standard telephone, xDSL, SR 1394, coaxial cable, twisted paircable, optical fiber, or any other suitable communication protocol,method, or medium.

In an embodiment of the present invention, a quality error bit rate isestablished for each subscriber unit 26. This quality error bit rate maybe based on the location of subscriber unit 26 within communicationsystem 20, the class of service assigned to subscriber unit 26, thegrade of service assigned to subscriber unit 26, the data ortransmission rate of service assigned to subscriber unit 26, or anyother suitable parameter. The quality error bit rate may be modifiedwhile subscriber unit 26 is within communication system 20 to reflectchanging conditions such as noise, demand, connectivity, or any othersuitable parameter. Applications providing services to subscriber unit26 may adjust these services based on the quality error bit rate. Forexample, an application providing streaming audio and video may reducethe frame update rate as noise increases, guaranteeing successfultransmission at a lower information rate. The information rate may befurther reduced to provide only still pictures and audio if conditionscontinue to worsen. The information rate may also be automaticallychanged if subscriber unit 26 moves between coverage areas 24 withdiffering transmission capabilities or loads.

Control of the information rate may be achieved by having subscriberunit 26 monitor a signaling channel transmitted by access point 22 foreach coverage area 24. This signaling channel informs subscriber unit 26when to transmit information, how much information to transmit, theinformation transmission rate, and the like. The signaling channel maybe controlled by a central supervisor, described below.

In an embodiment of the present invention, bandwidth on communicationlink 28 is only consumed when packets containing information aretransmitted. For example, each subscriber unit 26 surrenders bandwidthon communication link 28 when not sending or receiving an informationpacket. Packets to be transmitted are queued based on order of arrival,priority, a combination of arrival order and priority, or the like.Subscriber unit 26 monitors a signaling channel transmitted by accesspoint 22 for each coverage area 24. Subscriber unit 26 only consumesbandwidth when instructed to transmit by the signaling channel or whenreceiving packets.

Each access point 22 communicates with at least one distribution point40. Distribution point 40 contains both routing and switchingfunctionality. Access point 22 may be in contact with one or more radioaccess distribution points 40 over radio link 42, may be wired or cabledto distribution point 40 through wireline link 44, or may be packagedwith distribution point 40. Access point 22 may also be transformed intodistribution point 40, permitting access point 22 to route traffic thatneither originated nor terminated with any of its serviced subscriberunits 26. Distribution point 40 is in communication with at least oneadditional distribution point 40, the collection of interconnecteddistribution points forming a network of distribution points, showngenerally by 41. Two distribution points may be connected by radio link46 or wireline link 48.

Distribution points 40 may route packets within distribution pointnetwork 41 under a variety of protocols such as ATM, TCP/IP, 802.x, orthe like. In a preferred embodiment, distribution point 40 includes anATM/IP switch. Distribution point 40 then operates at both the IProuting and ATM switching layers or, in terms of the Open SystemsInterconnection (OSI) standard, at both the network layer and the datalink layer.

The IP layer operates with a link-state protocol such as the openshortest path first (OSPF), quality OSPF (Q-OSPF), or internal gatewayrouting protocol (IGRP) and its derivatives. The IP layer operates as asingle autonomous system (AS) within the IP frame of reference. Eachsystem 20 will be allocated a unique and unambiguous AS number forsystem management. IP addresses for system 20 will use a private IPaddress space that cannot be routed within public systems such as theInternet. Subscriber units 26 within system 20 may be permitted accessto the private IP address space or may be excluded from the private IPaddress space. When private IP address space is used for subscriberunits 26, a network address translator (NAT) within system 20 allowssubscriber units 26 access to the Internet. The ATM layer operates withthe private network node interface (PNNI) routing protocol. ATM endsystem addresses (AESAs), managed by the service provider for system 20,are used by distribution point network 41.

The ATM network carries voice traffic and may carry data. Through PNNI,the ATM/IP switch participates in switched or signaled virtualconnections (SVCs). When subscriber unit 26 within system 20 requiresvoice connectivity, it signals such a request, which is serviced bydistribution point 40 receiving that request. The IP network coresidingwith the ATM network is used for delay insensitive data applicationsrequired by subscriber units 26. The IP network is also used for allnetwork management, including management of ATM/IP switches, subscriberunits 26, gear associated with distribution points 40, and any othersuitable network component. This includes functions such as alarming,monitoring, recovery systems, and the like. While described in thecontext of a wireless network application, it is readily apparent thatATM/IP routing as described herein may be applied to wireline and mixedwireline-wireless systems as well.

Each distribution point 40 receives an information packet from eitheranother distribution point 40, from subscriber unit 26 in communicationwith distribution point 40 through access point 22, or from an externalcommunication system. If distribution point 40 determines theinformation packet is destined for subscriber unit 26 within coveragearea 24 of access point 22 in communication with distribution point 40,distribution point 40 forwards the packet to access point 22 formingcoverage area 24 containing destination subscriber unit 26. Ifdistribution point 40 determines the information packet is destined forsubscriber unit 26 in coverage area 24 formed by access point 22 incommunication with a different distribution point 40, distribution point40 forwards the packet to one of distribution points 40 in communicationwith distribution point 40. Hence, no central MSC is required forrouting. Distributed routing removes delays caused by central switching,increases the robustness of the communication system 20, increasesnetwork efficiency, and permits simplified expansion or reduction ofcommunication system 20 by automatically adding or removing distributionpoints 40.

A third option is that distribution point 40 determines that theinformation packet is destined for a destination not part ofcommunication system 20. Special distribution points, such as gateway50, provide a bridge to additional communication systems 52 includingwireless and wireline telecommunication systems, video distributionsystems, computer network systems such as the Internet, packet systems,frame systems, ATM systems, IP systems, private networks, and any othersuitable communication or information system. If distribution point 40determines the information packet is destined for delivery outside ofcommunication system 20, distribution point 40 forwards the packet toone of distribution points 40 in communication with gateway 50.

In an embodiment of the present invention, communication system 20includes communication system interface device 54 operative to formatinformation contained in the information packet to pass throughtelecommunication system 52. Communication system interface device 54may be incorporated into gateway 50 or may be a separate component ofcommunication system 20. Distribution point 40 receives at least oneinformation packet from the telecommunication system interface device 54and determines if the at least one information packet destination is tosubscriber unit 26 within coverage area 24 of access point 22 incommunication with distribution point 40. Distribution point 40 forwardsthe at least one information packet to access point 22 defining coveragearea 24 containing subscriber unit 26 if the information packetdestination is to subscriber unit 26 within coverage area 24 of accesspoint 22 in communication with distribution point 40 and forwards the atleast one information packet to one of the additional distributionpoints 40 in communication with distribution point 40 otherwise.

Each distribution point 40 communicates with supervisor 56. Supervisor56 tracks the locations of subscriber units 26 within communicationsystem 20, identifying with which distribution point 40 each subscriberunit 26 is currently communicating. Supervisor 56 manages transmissionpriorities based on parameters including load, information type, servicerequests, location, grade of service, information transfer rates, or anyother suitable parameter. Supervisor 56 may also serve as a collectionpoint for alarms and performance measuring of communication system 20.Supervisor 56 may further include or interface with billing andauthentication services.

In an embodiment of the present invention, supervisor 56 also assigns anaddress to each distribution point 40 as distribution point 40 is addedto communication system 20. Supervisor 56 provides each distributionpoint 40 with a logical address and a listing indicating to whichadditional distribution point 40 in communication with distributionpoint 40 information packets should be forwarded for each possibledestination distribution point 40. The listing may be based onmaintaining a minimum quality of service in the path throughdistribution point network 41 to the destination distribution point 40.Supervisor 56 periodically assesses the performance of network 41 bysending test messages. Reports may also be generated by distributionpoints 40 attempting to communicate with target addresses.

Supervisor 56 is shown in FIG. 1 as a separate component individuallyconnected to each distribution point 40. Alternatively, communicationbetween supervisor 56 and distribution points 40 may be through radiolinks 46 and wireline links 48. Supervisor 56 may be one or moreseparate components of communication system 20, may be incorporated intoone of distribution points 40, or may be distributed amongst multipledistribution points 40.

In an embodiment of the present invention, a distribution point may beautomatically added to or removed from distribution point network 41.When new distribution point 40 is first inserted into communicationsystem 20, new distribution point 40 transmits a signature signal.Existing distribution points 40 within range of new distribution point40 receive the signal and report it to supervisor 56. Supervisor 56 thendetermines if new distribution point 40 will be added to network 41. Ifso, supervisor 56 assigns new distribution point 40 a routing addressand informs network 41 as needed. Each existing distribution point 40 indistribution point network 41 is provided with an indication as to whichdistribution point 40 in communication with existing distribution point40 each information packet having a destination address specifying thenew distribution point 40 is to be forwarded. If a distribution point 40is removed from network 41, remaining distribution points 41 report theabsence of removed distribution point 40 to supervisor 56. Supervisor 56then informs network 41 as needed.

In an embodiment of the present invention, each subscriber unit 26 isautonomously registered with communication system 20 when subscriberunit 26 first enters coverage area 24 within communication system 20.Each subscriber unit 26 maintains registration as subscriber unit 26moves from one coverage area 24 into another coverage area 24 withincommunication system 20 and is autonomously deregistered when subscriberunit 26 leaves communication system 20. To accomplish automaticregistration and deregistration of subscriber units 26, each accesspoint 22 periodically reports the status of subscriber units 26 withinany controlled coverage area 24 to supervisor 56 performing registrationand authentication. Each access point 22 communicates with subscriberunits 26 to determine status. When a subscriber unit 26 voluntarilyenters or leaves coverage area 24, such as by powering up or down,subscriber unit 26 transmits a particular signal to access point 22.Information is also received from subscriber unit 26 in response toperiodic queries from network 20. Access point 22 may determine theabsence of subscriber unit 26 from coverage area 24 if no communicationis received after a particular time interval. Algorithms for registeringand deregistering subscriber units 26 may be based on various factorsincluding quality of service, traffic, location, service type, networktopology, and the like.

Referring now to FIG. 2, a block diagram of a distribution pointaccording to an embodiment of the present invention is shown.Distribution point 40 includes one or more front end communicationinterfaces 100, each front end interface communicating with one accesspoint 22. In one configuration, access point 22 is packaged withdistribution point 40. Front end interface 100 may provide a plug-inport for receiving access point 22. In another configuration, front endinterface 100 connects to antenna 102 for establishing radio link 42with access point 22. In a further configuration, front end interface100 accepts wireline link 44 connecting distribution point 40 withaccess point 22. Front end interface 100 operates using a standardpacket switching protocol such as, for example, ATM25. Each front endcommunication interface 100 passes information packets through commonfront end switch interface 104 operating under a packet protocol such asATM, TCP/IP, 802.x, or the like.

Distribution point 40 also includes back end communication interfaces106 for connecting distribution point 40 with additional distributionpoints 40, with supervisor 56, and, if distribution point 40 is agateway 50, with telecommunication systems, private network systems,video distribution systems, the Internet, or the like. This may betypically referred to as back haul communication. In one configurationof the present invention, back end interface 106 connects to antenna 108for establishing radio link 46 with another distribution point 40. Inanother configuration, back end interface 104 accepts wireline link 44connecting distribution point 40 with another distribution point 40. Ina preferred embodiment, back end interface 106 accepts modules 110 forinterfacing through a variety of protocols and media such as ATM25, DS1,DS3, OC3, 1000Base-T, 100Base-T, and the like. Each back endcommunication interface 106 passes information packets through commonback end switch interface 112 operating under a packet protocol such asATM, TCP/IP, or the like. In a preferred embodiment, distribution point40 dynamically allocates bandwidth when the information packet isforwarded to one of the additional distribution points 40 incommunication with distribution point 40.

Intelligent packet switch 114 received information packets throughcommon front end switch interface 104 and common back end switchinterface 112 and routes the packets between front end interfaces 100and back end communication interfaces 106. Switch 114 may be a packetswitching device as is known in the art such as an ATM switch, an IPswitch, a TDM switch, a switch working under the 802.11 specification,or any other suitable alternative or combination having the requiredswitching functionality. In an embodiment of the present invention,switch 114 includes an ATM portion for routing voice, video and data,and an IP portion for real-time dynamic data routing and non-real timedata routing as well as administration, management, and network topologycontrol.

In an embodiment of the present invention, distribution point 40 isenclosed in an environmentally sealed package. This permits distributionpoint 40 to be mounted outside, such as on a pole or the side of abuilding. In keeping with the invention, however, distribution point 40need not be outside so long as it can communicate with access points 22,additional distribution points 40, supervisor 56, and any other suitablenetwork component.

Referring now to FIG. 3, a schematic drawing illustrating animplementation of a communication system according to an embodiment ofthe present invention is shown. This implementation provides an exampleincluding interfaces between communication system 20 and a variety ofexternal communication systems 52.

Communication system 20 includes wireless service location registers(WSLRs) 200 providing common subscriber and service databases. Each WSLR200 communicates with at least one distribution point 40 and oneadditional communication system 52. Connections between WSLRs 200 andcommunication systems 52 are not shown in FIG. 3 for clarity. Each WSLR200 provisions requested services from additional communication system52. For example, WSLR 200 may provide centralized mobility and locationmanagement. Supervisor 56 determines which WSLR 200 will provisionservices based on the distribution point 40 through which subscriberunit 26 requesting services is currently communicating. A device thatmay serve as WSLR 200 is described in U.S. Pat. No. 5,974,331 titled“Method And System For Dynamically Assigning Features And Users ToWireline Interfaces,” to Cook et al., which is herein incorporated byreference. Call agents may also function as WSLR-like devices to map orintegrate additional communication systems with system 20.

Communication system 20 may also include multi-service platform (MSP)202. MSP 202 provides access to wireline telephone systems (PSTN). Thismay be accomplished through GR-303 compliant connection 204. Signalingpoint of interface (SPOI) 206 serves as the demarcation point betweencommunication system 20 and external communication system 52. In theexample shown, GR-303 connection 204 connects wireline provider 208,serving wired customers 210, with communication system 20. MSP 202 mayintegrate both PSTN and IP networks as well as provide enhancedcircuit/packet switch services.

At least one gateway 212 supports MSP 202. Communication system 20 mayinclude, for example, voice-over-ATM (VoATM) to GR-303 gateways andvoice over IP (VoIP) to GR-303 gateways. Gateway 212 serves as aprotocol agent, converting information packets to a format acceptable toadditional communication system 52. A determination as to which gateway212 will process an information packet may be based on informationcontained within the information packet. Gateways 212 may be connectedto MSP 202 by GR-303 compliant connection 214.

Communication system 20 may also include gateway 216 connectingcommunication system 20 with external data network 52 such as theInternet or a private data network interconnecting network users 218.Gateway 216 may, for example, convert between various packet-basedstandards such as H.323 and SIP.

Communication system 20 may also include gateway 220 interfacingcommunication system 20 with external SS7 network 52 represented bysignal transfer point (STP) 222. Gateway 220 communicates with STP 222through ISUP compliant connection 224 which permits setting up andtaking down trunk calls, calling party information services, callstatus, and any other suitable network function, by passing signalinginformation through SS7 network 52 to wireline provider 208 under thecontrol of integrated services control point (ISCP) 226.

Communication system 20 may also include unified message center (UMC)228. Unified messages, also known as integrated messages, permitmessages from a variety of sources such as telephone, email, fax,reports, compound documents, or any other suitable information orcommunication device, to be summarized and presented on a single medium,such as a personal computer. Messages may even be translated from onemedia type to another. UMC 228 supports unified message applicationswithin communication system 20. In an embodiment, UMC 228 communicateswith wireline provider 208, permitting greater integration, flexibilityand access to messages.

Connection controller 230 controls access to gateways 50, 202, 212, 216,220, or any other suitable interface. For example, connection controller230 may manage voice over ATM to GR-303 access, voice over IP to GR-303access, H.323/SIP to Internet remote access, SS7 to IP access, and thelike. Connection controller 230 may also support information rateadaptation including open application processor interfaces and robustapplication development platforms.

Referring now to FIGS. 4-6, drawings illustrating dynamic growth of adistribution point network according to an embodiment of the presentinvention are shown. An initial configuration for system 20 is shown inFIG. 4. ATM/IP switch 300 is in communication with supervisor 56 throughATM virtual connection 302. In this simple configuration, ATM/IP switch300 may be functioning as access point 22. ATM/IP switch 300 may obtainan IP address and an ATM address either manually or automatically.

ATM/IP switch 300 automatically requests addresses by first broadcastingan ATM request in an IP packet over virtual connection (VC) 302.Supervisor 56 forwards this request to address server 304. Addressserver 304 responds by allocating unique AESA 306 to the addressassignment client in ATM/IP switch 300, which updates the ATM layer withnew address 306. The address assignment client in ATM/IP switch 300 nextrequests from address server 304 an IP address, again using IP as thetransport service over pre-existing ATM VC 302. Address server 304forwards IP address 308 to ATM/IP switch 300. ATM/IP switch 300 thenrequests address pools for ATM and IP. Address server 304 responds bysuppling AESA pool 310 and IP address pool 312. Pools of addresses 310,312 are used by switch 300 when functioning as distribution point 40 insupport of other distribution points 40 and access points 22.

Referring now to FIG. 5, a drawing illustrating the addition of a secondaccess point is shown. Access point 22 has the capability to function asa distribution point 40. As new access points 22 are subtended from anexisting access point 22, existing access point 22 becomes adistribution point 40. Each distribution point 40 continues tocommunicate with its initially connected distribution point 40 and withother distribution points 40 as they are provisioned. As new links 46,48 between distribution points are created, distribution points 40 formpeer relationships at both the ATM layer and the IP layer. Distributionpoints 40 are always peers at the IP and ATM layer, while access points22 are clients of distribution points 40. As such, each ATM/IP switch300 functions as a server when operating as distribution point 40 and asa client when operating as access point 22.

When new ATM/IP switch 320 is instantiated as access point 22, it willautomatically request an ATM address in an IP packet address assignmentrequest. This IP packet will be sent in an ATM frame over radio link 46to IP/ATM switch 300 functioning as distribution point 40 using apre-existing ATM VC. IP/ATM switch 300 will allocate unique ATM address322 from AESA pool 310 and unique IP address 324 from IP address pool312. ATM/IP switch 320 then sends a directed request to address server304 and receives its own AESA pool 326 and IP address pool 328.

Referring now to FIG. 6, a hierarchical routing network is shown.Address server 304 assigns AESA pool 310 and IP address pool 312 as eachATM/IP switch 300 is added. By handling all requests for address pools310, 312, address server 304 maintains a hierarchy of addresses for bothATM and IP layers. Address server 304 constructs routing tables for eachATM/IP switch 300 indicating to which directly connected ATM/IP switch300 each incoming packet should be routed if the packet is not destinedto subscriber unit 26 serviced by that ATM/IP switch 300. Thus, routingtables are cohesive, reflecting the view of communication system 20 seenby each ATM/IP switch 300. Address server 304 also constructs forwardequivalency class (FEC) tables permitting ATM/IP switch 300 to routepackages based on package contents. FECs can be seen as either thevirtual path identifier (VPI) portion of the ATM VPI/VCI or as theentire VPI/VCI, and are enabled by the routing protocols at the IP andPNNI layers.

New routing elements are dynamically added to a network of routingelements by establishing a connection between the new routing elementand an existing routing element in the network of routing elements. Atleast one address is assigned to the new routing element, each assignedaddress coming from a pool of addresses maintained at the existingrouting element. At least one pool of addresses is issued to the newrouting element. The one or more pool of addresses permitting the newrouting element to dynamically add yet another new routing element tothe network of routing elements.

In an embodiment of the present invention, a method of dynamicallyadding a routing element to a distributed communications includesestablishing an ATM virtual connection with an existing distributionpoint already part of the communications network. An ATM end useraddress is requested from the existing distribution point. An ATM enduser address is obtained from the existing distribution point, the ATMend user address allocated from a pool of ATM end user addresses in theexisting distribution point. An IP address is requested from theexisting distribution point. An IP address is obtained from the existingdistribution point, the IP address allocated from a pool of IP addressesin the existing distribution point. Preferably, a pool of ATM end useraddresses is requested and received from an address server. A pool of IPaddresses is requested and received from the address server. An ATM enduser address from the pool of ATM end user addresses and an IP addressfrom the pool of IP addresses may be assigned to a new routing elementrequesting to be added to the communications network.

In an embodiment of the present invention, when a new distribution pointis added to a network of distribution points, a connection isestablished between the new distribution point and at least one existingdistribution point in the network of distribution points. A peer-to-peerrelationship is formed at the OSI network layer between the newdistribution point and the at least one existing distribution point. Apeer-to-peer relationship is formed at the OSI data link layer betweenthe new distribution point and the at least one existing distributionpoint.

In an embodiment of the present invention, when an access point is addedto a network of distribution points, a connection is established betweenthe access point and at least one existing distribution point in thenetwork of distribution points. A client-server relationship is formedat the OSI network layer between the access point client and the atleast one existing distribution point server. A client-serverrelationship is formed at the OSI data link layer between the accesspoint and the at least one existing distribution point server.

In an embodiment of the present invention, when an ATM/IP switch 300 isremoved from communication system 20, all of the addresses 306, 308 andaddress pools 310, 312 associated with the removed switch 300 arereleased. Addresses 306, 308 and address pools 310, 312 may beinstantiated at distribution point 40 which originally supplied removedswitch 300 with addresses 306, 308, may be sent to supervisor 56, or maybe split with addresses 306, 308 returning to distribution point 40 andaddress pools 310, 312 returning to supervisor 56.

When subscriber unit 26 first enters communication system 20, it isdetected and serviced by access point 22. Subscriber unit 26 is providedwith one or more addresses, each address routable within at least thelocal hierarchy of ATM/IP switches 300. If subscriber unit 26 enters therange of a new access point 22, new access point 22 sends out a floodingFEC routing update for the ATM address of subscriber unit 26. Previouslyservicing access point 22 removes subscriber unit 26 from its own FECupon receiving the FEC update. Any subsequent ATM packets received bypreviously servicing access point 22 are discarded.

When subscriber unit 26 changes access points 22, the IP routing portionof system 20 moves the IP address of subscriber unit 26 from one FECclass to another. Any IP packets remain untouched, with only a label orequivalence changed. In one embodiment, the label is the VPI portion ofthe VC. In another embodiment, multiprotocol label switching (MPLS) isused to provide an additional label. In either case, the IP address andvirtual connection identifier (VCI) are retained.

Referring now to FIG. 7, a schematic drawing illustrating a network ofdistribution points routing packets based on forwarding equivalencyclasses is shown. Each distribution point contains an FEC table 400 usedto route packets received from and destined to subscriber units 26.Forwarding equivalency class table 400 contains one entry for eachforwarding equivalency class 402. In the embodiment shown, there is oneFEC 402 corresponding to each access point 22. When subscriber unit 26is first detected by access point 22, the address for subscriber unit 22is placed in the equivalency class 402 corresponding to the detectingaccess point 22. The address is typically an IP address. This may bedone by broadcasting from detecting access point 22 or, preferably, isdone by supervisor 56 after supervisor 56 receives a message indicatingsubscriber unit 26 has been detected by access point 22.

FEC table 400 in each distribution point 40 contains the nextdestination for each FEC 402. Typically, destinations are otherdistribution points 40, access points 22 serviced by distribution point40, gateways 50, and other suitable points for routing, switching,servicing, distributing, and the like. When a packet destined forsubscriber unit 26 is received by distribution point 40, distributionpoint 40 determines to which FEC subscriber unit 26 is assigned,determines to which destination the packets in that FEC are routed, andforwards the packet to the determined destination.

Referring now to FIG. 8, a schematic drawing illustrating forwardingequivalency class updating to track a moving subscriber unit is shown.If subscriber unit 26 is mobile or portable, as indicated by U1 in FIG.8, subscriber unit 26 may move out of coverage area 24 for one accesspoint 22 and into coverage area 24 for a new access point 22. Theaddress for subscriber unit 26 is then moved from FEC 402 of originalaccess point 22 into FEC 402 for new access point 22. In an embodiment,when original access point 22 is no longer in communication withsubscriber unit 26, original access point 22 broadcasts a message todistribution points 40 and supervisor 56. If original access point 22subsequently receives any packets for subscriber unit 26, originalaccess point forwards these packets back into distribution point network41. If the packets are sequentially indicated, such as IP packets,correct order will be established by subscriber unit 26 when packets arereceived.

While embodiments of the invention have been illustrated and described,it is not intended that these embodiments illustrate and describe allpossible forms of the invention. Rather, the words used in thespecification are words of description rather than limitation, and it isunderstood that various changes may be made without departing from thespirit and scope of the invention.

1. A method of routing information packets in a distributed routingnetwork comprising: determining a forwarding equivalency class for allsubscriber units accessing the network at an access point, eachforwarding equivalency class comprising the accessing access point andreflecting information pertaining to at least one of quality error bitrate, information packet content, priority level, bandwidth requirement,signal quality, and virtual path identifier information; updating theforwarding equivalency class for each subscriber unit if the subscriberunit accesses the network at a different access point; determining anext distribution point to forward an information packet based on theforwarding equivalency class for a destination subscriber unit; anddistributing the forwarding equivalency class for each subscriber unitto each distribution point.
 2. A method of routing packets in adistributed routing network as in claim 1 wherein the packets are IPpackets.
 3. A method of modifying the routing of packets through anetwork of distribution points, the packets destined for a subscriberunit accessing the network through a first access point, the methodcomprising: determining that the subscriber unit is accessing thenetwork through a second access point; assigning the subscriber unit toa forwarding equivalency class based on the second access point, theforwarding equivalency class being distributed to each distributionpoint and reflecting information pertaining to at least one of qualityerror bit rate, information packet content, priority level, bandwidthrequirement, signal quality, and virtual path identifier information;routing packets destined for the subscriber unit through the network ofdistribution points based on the assigned forwarding equivalency class.4. A method of modifying the routing of packets through a network ofdistribution points as in claim 3 wherein determining that thesubscriber unit is accessing the network through a second access pointcomprises transmitting an indication for the second access point throughthe network of distribution points.
 5. A method of modifying the routingof packets through a network of distribution points as in claim 3further comprising: determining that the subscriber unit is no longeraccessing the network through a first access point; and broadcasting anindication for the first access point through the network ofdistribution points.
 6. A method of modifying the routing of packetsthrough a network of distribution points as in claim 3 wherein thesubscriber unit is assigned an IP address used to route packets to thesubscriber unit.
 7. A method of modifying the routing of packets througha network of distribution points as in claim 3 further comprisingnotifying the distribution points in the network of distribution pointsof the changed forwarding equivalency class.
 8. A method of modifyingthe routing of packets through a network of distribution points as inclaim 3 wherein assigning the subscriber unit to a forwardingequivalency class comprises: receiving a determination that thesubscriber unit is accessing the network through a second access point;and broadcasting the assignment of the forwarding equivalency class toeach distribution point in the network of distribution points.
 9. Amethod of modifying the routing of packets through a network ofdistribution points as in claim 8 wherein receiving is at a supervisorand broadcasting is from the supervisor.
 10. A communication system fordistributing packetized information comprising a plurality ofdistribution points forming a distributed routing network, eachdistribution point in communication with at least one other distributionpoint, each distribution point operative to: (a) maintain a forwardingequivalency class for subscriber units accessing the communicationsystem, the forwarding equivalency class comprising an accessing accesspoint and reflecting information pertaining to at least one of qualityerror bit rate, information packet content, priority level, bandwidthrequirement, signal quality, and virtual path identifier information,(b) update the forwarding equivalency class for each subscriber unitthat accesses the communication system through a different point in thecommunication system, (c) determine the next distribution point toforward an information packet based on the forwarding equivalency classfor a destination subscriber unit specified in the information packet;and (d) distributing the forwarding equivalency class for eachsubscriber unit to each distribution point.
 11. A communication systemfor distributing packetized information as in claim 10 wherein thepackets are IP packets.